Evidence of genotoxicity and cytotoxicity of X-rays in the oral mucosa epithelium of adults subjected to cone beam CT.

OBJECTIVES: To assess cytological evidence of genotoxicity and cytotoxicity of X-rays in oral exfoliated cells of adults subjected to partial and total cone beam CT (CBCT) (stitching module) by means of micronuclei frequency, associated with counting of degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis, buds and broken eggs), besides comparing the partial and total CBCT (stitching module) in search of possible differences in the nature and/or intensity of the effects. METHODS: 29 adults who were referred to total or partial CBCT were selected. All CBCT were performed with a Carestream CS 9000 3D scanner (Carestream Health Inc., Rochester, NY). Material collection was done immediately before CBCT and 10 days later, by scraping the left and right cheek mucosa with a plastic spatula. Statistical analysis was performed using the Wilcoxon test (paired data), at a significance level of 5%. RESULTS: The statistically significant difference was noted in the frequency of micronucleated cells for both partial and total acquisition (p = 0.008 and p < 0.001, respectively). Regarding to cytotoxicity, there was a statistically significant difference for both partial and total acquisition (p < 0.001 and p < 0.001, respectively). CONCLUSIONS: The partial and total CBCT seems to offer risks of inducing genetic damage. In addition both forms of CBCT acquisition have promoted the induction of cytotoxic nuclear alterations.

Plasmacytoid myoepithelioma of minor salivary glands: report of case with emphasis in the immunohistochemical findings.

Myoepithelioma is a rare benign tumor of the salivary glands and is usually seen in the parotid gland and the minor salivary glands. It was once considered to be a type of pleomorphic adenoma (PA), but myoepitheliomas are today believed to be relatively aggressive tumors. Myoepitheliomas are most common in young adults between the ages of 30 and 50 and there are very few cases reported in individuals less than 18 years of age. We report a case of myoepithelioma located in the hard palate in a 15-year-old Brazilian male. The tumor was composed of plasmacytoid myoepithelial cells. An analysis of the immunohistochemical profile of the tumor cells showed positivity for vimentin, S-100 protein, and glial fibrillary acidic protein (GFAP), but not for smooth muscle actin (α-SMA) and cytokeratin 14 (CK14). We report this case because of the rarity of this tumor, especially in adolescents. We also discuss the histological parameters of the differential diagnosis of this tumor as well as its immunohistochemical profile.